For long exposure times, many CCD cameras are cooled to reduce thermal noise and achieve higher image quality. CCD cameras are grouped into three categories:
- no cooling - passive cooling via cooling fins - active cooling (e.g. using a fan and Peltier element)
The bit depth is also referred to as the dynamic range of a chip. The number of bits in a picture also determines how many different shades of grey can be displayed. The depth of the image information depends directly on it. In an image taken with 1 bit depth, you will only see black and white dots. In this case, you can hardly call it a picture. Many details that the naked eye can discern are missing. 16 bits means the presentation of more than 65.000 shades of grey.